OAI/Analysis/KadisonKastler/FourierIntegralL2.lean

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Agreement of the integral and Hilbert-space Fourier transforms

The reproducing kernels used by Hardy evaluation are integrable square-integrable functions, rather than Schwartz functions. This bridge identifies their explicit integral transforms with the existing unitary Fourier transform.

  1. theorem OAI.KadisonKastler.fourier_toLp_of_integrable line 21

    Source documentation

    An integrable scalar function whose Fourier transform is square integrable has the same transform in the concrete L² Fourier representation.

    theorem fourier_toLp_of_integrable {f : ℝ → ℂ} (hf : Integrable f)
        (hf2 : MemLp f 2) (hF2 : MemLp (𝓕 f) 2) :
        𝓕 (hf2.toLp f) = hF2.toLp (𝓕 f) := by
    …
  2. theorem OAI.KadisonKastler.fourierInv_toLp_of_integrable line 48

    Source documentation

    An integrable scalar function whose Fourier transform is square integrable has the same transform in the concrete L² Fourier representation.

    theorem fourierInv_toLp_of_integrable {f : ℝ → ℂ} (hf : Integrable f)
        (hf2 : MemLp f 2) (hF2 : MemLp (𝓕⁻ f) 2) :
        𝓕⁻ (hf2.toLp f) = hF2.toLp (𝓕⁻ f) := by
    …